How Much Does the Universe Expand Every Day? A Simple Explanation
Have you ever wondered how big the universe is and how fast it is growing? If so, you are not alone. Many people are curious about the size and expansion of the universe, and scientists have been trying to measure it for decades. In this article, we will explain what the expansion of the universe means, how it is measured, and how much it grows every day.
What is the expansion of the universe?
The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time 1 It is an intrinsic expansion; the universe does not expand “into” anything and does not require space to exist “outside” it. To any spectator in the universe, it appears that all galaxies (excluding those bound by gravity) recede at average rates proportionate to their distance from the observer. This is known as Hubble’s law, named after Edwin Hubble, who discovered this phenomenon in 1929.
The expansion of the universe is a key feature of Big Bang cosmology, which is the scientific model that describes the origin and evolution of the universe. According to this model, the universe began as a very hot and dense state about 13.8 billion years ago, and has been expanding and cooling ever since. The expansion of the universe also affects its geometry, which can be flat, curved, or open depending on the amount and distribution of matter and energy in it.
How is the expansion of the universe measured?
One way to measure the expansion of the universe is to use standard candles, which are objects whose brightness or luminosity can be calculated independently of their distance. For example, Type Ia supernovae are exploding stars that have a consistent peak brightness, so by comparing their observed brightness with their expected brightness, we can estimate how far away they are. By measuring their redshift, which is the amount by which their light is stretched or shifted to longer wavelengths due to the expansion of space, we can also estimate how fast they are moving away from us. By plotting these two quantities against each other for many supernovae, we can obtain a value for the Hubble constant, which is the rate of expansion of the universe at present.
Another way to measure the expansion of the universe is to use standard rulers, which are objects whose size or angular diameter can be calculated independently of their distance. For example, baryon acoustic oscillations (BAOs) are ripples in the distribution of matter that were imprinted in the early universe by sound waves traveling through it. These ripples have a characteristic scale that can be measured by observing how galaxies cluster together. By measuring their redshift, we can also estimate how fast they are moving away from us. By comparing these two quantities for different redshifts, we can obtain a value for how the Hubble constant changes over time.
How much does the universe expand every day?
According to recent measurements by NASA, 2 based on data from Type Ia supernovae and other sources, the current value of the Hubble constant is about 74.3 kilometers per second per megaparsec (km/s/Mpc). This means that for every 3.26 million light-years (or one megaparsec) that you move away from Earth, the universe is expanding at a rate of about 74.3 kilometers per second.
To calculate how much the universe expands every day, we need to multiply this rate by 24 hours and by 365 days. This gives us:
74.3 km/s/Mpc x 24 x 60 x 60 x 365 = 2.34 billion km/Mpc/year
This means that for every megaparsec that you move away from Earth, the universe expands by about 2.34 billion kilometers every year.
Consider the following instances to put this into context:
The nearest galaxy to our own Milky Way is Andromeda, which is about 2.5 million light-years away from us. This means that Andromeda is receding from us at a speed of about 186 km/s due to the expansion of space. This also means that Andromeda gets farther away from us by about 5.85 million kilometers every year.
The most distant galaxy ever observed is GN-z11, which is about 13.4 billion light-years away from us. This means that GN-z11 is receding from us at a speed of about 1 million km/s due to the expansion of space. This also means that GN-z11 gets farther away from us by about 31 trillion kilometers every year.
As you can see, these numbers are very large and hard to comprehend. However, they are not the whole story. The expansion of the universe is not constant, but rather accelerating. This means that the rate of expansion is increasing over time, and will continue to do so in the future. This is due to the presence of dark energy, which is a mysterious form of energy that makes up about 70% of the mass and energy in the universe, and that causes the expansion of space to speed up. Scientists do not yet fully understand what dark energy is or how it works, but they are working hard to find out.
Conclusion
In this article, we have explained what the expansion of the universe means, how it is measured, and how much it grows every day. We have also learned that the expansion of the universe is accelerating due to dark energy, which is one of the biggest mysteries in modern cosmology. We hope that this article has helped you understand more about the amazing and fascinating universe we live in.
Read also: NASA, Rocket Lab Announce Coverage